Po utworzeniu Welsh Premier League w 1992 roku Welsh Football League Division One razem z Cymru Alliance stała drugim poziomem rozgrywek w Walii.
Nazwy 1904–1909: Rhymney Valley League Division 1 1909–1912: Glamorgan League Division 1 1912–1964: Welsh Football League Division 1 1964–1983: Welsh Football League Premier Division 1983–1992: Welsh Football League National Division od 1992: Welsh Football League Division 1
Skład ligi w sezonie 2019/2029 Aberbargoed Buds Abergavenny Town AFC Llwydcoed Bridgend Street Caldicot Town Croesyceiliog Dinas Powys Garden Village Goytre Monmouth Town Penydarren BGC Pontardawe Town Port Talbot Town Risca United Ton Pentre Trefelin BGC
Zwycięzcy rozgrywek Rhymney Valley League Division 1 1905 - Aberdare 1906 - Rogerstone 1907 - Cwmaman 1908 - Ton Pentre 1909 - Aberdare Glamorgan League Division 1 1910 - Treharris 1911 - Merthyr Town 1912 - Aberdare Welsh Football League Division 1 1913 - Swansea Town Reserves 1914 - Llanelly 1915 - Ton Pentre 1920 - Mid Rhondda 1921 - Aberdare 1922 - Porth 1923 - Cardiff City Reserves 1924 - Pontypridd 1925 - Swansea Town Reserves 1926 - Swansea Town Reserves 1927 - Barry Reserves 1928 - Newport County Reserves 1929 - Cardiff City Reserves 1930 - Llanelly 1931 - Merthyr Town Reserves 1932 - Lovell's